Q. Which of the following includes both microscopic plants like algae and animals like crustaceans and protozoans found in all aquatic ecosystems, except certain swift moving waters? Answer:
Plankton
Notes: Plankton includes both microscopic plants like algae (phytoplankton) and animals like crustaceans and protozoans (zooplankton). They are found in all aquatic ecosystems, except in certain swift moving waters.